yo-yo

a spoollike toy consisting of two thick wooden, plastic, or metal disks connected by a dowel pin in the center to which a string is attached, one end being looped around the player's finger so that the toy can be spun out and reeled in by wrist motion.

2.

something that fluctuates or moves up and down, especially suddenly or repeatedly.

3.

Slang. a stupid, foolish, or incompetent person.

adjective

4.

Informal. moving up and down or back and forth; fluctuating; vacillating:

yo-yo prices; a yo-yo foreign policy.

verb (used without object)

5.

Informal. to move up and down or back and forth; fluctuate or vacillate:

Mortgage rates are still yo-yoing.

verb (used with object)

6.

Informal. to cause to yo-yo.

Origin of yo-yo

earlier, a U.S. trademark for such a toy (1932); recorded in 1915 as the name of a Philippine toy; of undetermined orig.

yo-yo

n.

1915, apparently from a language of the Philippines. Registered as a trademark in Vancouver, Canada, in 1932, the year the first craze for them began (subsequent fads 1950s, 1970s, 1998). The toy itself is much older and was earlier known as bandalore (1824). Figurative sense of any "up-and-down movement" is first recorded 1932. Meaning "stupid person" is recorded from 1970. The verb in the figurative sense is attested from 1967.